Extreme cold temperatures increase the risk of death among people with cardiovascular disease, according to new research.
Like freezing conditions brought heavy snow to much of the UK overnighta study in the journal Circulation warned people who suffered from conditions including irregular heartbeat were at greater risk when the weather gets rough.
UK weather updates: The coldest day of the year at below -15C
For every 1,000 cardiovascular deaths, researchers found that extremely cold days accounted for an extra nine.
The trend was less pronounced on days of extreme heat, which accounted for two more deaths.
That comes later Britain saw temperatures north of 40C in the summer, when excessive deaths among over 65s reached its highest level since 2004.
Of the types of heart disease, the largest number of extra deaths was found for people with heart failure, with nearly 13 on extremely cold days and nearly three on extremely hot days.
How was the study conducted?
The peer-reviewed global study was conducted by the Multi-Country Multi-City Collaborative Research Network.
It analyzed data for more than 32 million cardiovascular deaths – the leading cause of death globally – in 27 countries on five continents between 1979 and 2019.
Deaths were compared on the hottest and coldest 2.5% of days for each city with those on days that had “optimal temperature”, defined as the temperature associated with the lowest death rates.
“One in 100 cardiovascular deaths can be attributed to extreme temperature days, and temperature effects were more pronounced when looking at heart failure deaths,” said study co-author Haitham Khraishah, of the University of Maryland.
“Although we do not know the cause, this may be explained by the progressive nature of heart failure as a disease, which makes patients vulnerable to temperature effects.
“This is an important finding as one in four people with heart failure are readmitted to hospital within 30 days of discharge, and only 20% of patients with heart failure survive 10 years after diagnosis.”
Findings “show the importance of the fight against climate change”
More work is needed to develop strategies to mitigate the impact of extreme temperatures in the face of increasing climate change, the researchers conclude.
One proposal is to introduce targeted warning systems and advice for vulnerable people.
“We need to be on top of new environmental exposures,” said Barrak Alahmad, of Harvard University.
“I urge the professional cardiology organizations to provide guidelines and scientific statements on the intersection of extreme temperatures and cardiovascular health.
“In such statements, we can provide more guidance to healthcare professionals, as well as identify clinical data gaps and future priorities for research.”